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authorLinus Walleij <linus.walleij@linaro.org>2016-02-12 22:25:22 +0100
committerLinus Walleij <linus.walleij@linaro.org>2016-02-19 09:48:46 +0100
commit521a2ad6f862a28e2e43cb3e254a26bf0f9452e9 (patch)
tree94cc59e775b6691cf2aded1ef98bfb8a11c3f65a /tools/gpio
parentdf4878e969ccc047da45d2cd3af5d08031da1593 (diff)
downloadlinux-linaro-stable-521a2ad6f862a28e2e43cb3e254a26bf0f9452e9.tar.gz
gpio: add userspace ABI for GPIO line information
This adds a GPIO line ABI for getting name, label and a few select flags from the kernel. This hides the kernel internals and only tells userspace what it may need to know: the different in-kernel consumers are masked behind the flag "kernel" and that is all userspace needs to know. However electric characteristics like active low, open drain etc are reflected to userspace, as this is important information. We provide information on all lines on all chips, later on we will likely add a flag for the chardev consumer so we can filter and display only the lines userspace actually uses in e.g. lsgpio, but then we first need an ABI for userspace to grab and use (get/set/select direction) a GPIO line. Sample output from "lsgpio" on ux500: GPIO chip: gpiochip7, "8011e000.gpio", 32 GPIO lines line 0: unnamed unlabeled line 1: unnamed unlabeled (...) line 25: unnamed "SFH7741 Proximity Sensor" [kernel output open-drain] line 26: unnamed unlabeled (...) Tested-by: Michael Welling <mwelling@ieee.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'tools/gpio')
-rw-r--r--tools/gpio/gpio-utils.h2
-rw-r--r--tools/gpio/lsgpio.c91
2 files changed, 81 insertions, 12 deletions
diff --git a/tools/gpio/gpio-utils.h b/tools/gpio/gpio-utils.h
index b18209a45ad3..5f57133b8c04 100644
--- a/tools/gpio/gpio-utils.h
+++ b/tools/gpio/gpio-utils.h
@@ -16,6 +16,8 @@
#include <string.h>
+#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
+
static inline int check_prefix(const char *str, const char *prefix)
{
return strlen(str) > strlen(prefix) &&
diff --git a/tools/gpio/lsgpio.c b/tools/gpio/lsgpio.c
index 692233f561fb..5535ce81f8f7 100644
--- a/tools/gpio/lsgpio.c
+++ b/tools/gpio/lsgpio.c
@@ -26,12 +26,56 @@
#include "gpio-utils.h"
+struct gpio_flag {
+ char *name;
+ unsigned long mask;
+};
+
+struct gpio_flag flagnames[] = {
+ {
+ .name = "kernel",
+ .mask = GPIOLINE_FLAG_KERNEL,
+ },
+ {
+ .name = "output",
+ .mask = GPIOLINE_FLAG_IS_OUT,
+ },
+ {
+ .name = "active-low",
+ .mask = GPIOLINE_FLAG_ACTIVE_LOW,
+ },
+ {
+ .name = "open-drain",
+ .mask = GPIOLINE_FLAG_OPEN_DRAIN,
+ },
+ {
+ .name = "open-source",
+ .mask = GPIOLINE_FLAG_OPEN_SOURCE,
+ },
+};
+
+void print_flags(unsigned long flags)
+{
+ int i;
+ int printed = 0;
+
+ for (i = 0; i < ARRAY_SIZE(flagnames); i++) {
+ if (flags & flagnames[i].mask) {
+ if (printed)
+ fprintf(stdout, " ");
+ fprintf(stdout, "%s", flagnames[i].name);
+ printed++;
+ }
+ }
+}
+
int list_device(const char *device_name)
{
struct gpiochip_info cinfo;
char *chrdev_name;
int fd;
int ret;
+ int i;
ret = asprintf(&chrdev_name, "/dev/%s", device_name);
if (ret < 0)
@@ -41,32 +85,55 @@ int list_device(const char *device_name)
if (fd == -1) {
ret = -errno;
fprintf(stderr, "Failed to open %s\n", chrdev_name);
- goto free_chrdev_name;
+ goto exit_close_error;
}
/* Inspect this GPIO chip */
ret = ioctl(fd, GPIO_GET_CHIPINFO_IOCTL, &cinfo);
if (ret == -1) {
ret = -errno;
- fprintf(stderr, "Failed to retrieve GPIO fd\n");
- if (close(fd) == -1)
- perror("Failed to close GPIO character device file");
-
- goto free_chrdev_name;
+ perror("Failed to issue CHIPINFO IOCTL\n");
+ goto exit_close_error;
}
fprintf(stdout, "GPIO chip: %s, \"%s\", %u GPIO lines\n",
cinfo.name, cinfo.label, cinfo.lines);
- if (close(fd) == -1) {
- ret = -errno;
- goto free_chrdev_name;
+ /* Loop over the lines and print info */
+ for (i = 0; i < cinfo.lines; i++) {
+ struct gpioline_info linfo;
+
+ memset(&linfo, 0, sizeof(linfo));
+ linfo.line_offset = i;
+
+ ret = ioctl(fd, GPIO_GET_LINEINFO_IOCTL, &linfo);
+ if (ret == -1) {
+ ret = -errno;
+ perror("Failed to issue LINEINFO IOCTL\n");
+ goto exit_close_error;
+ }
+ fprintf(stdout, "\tline %d:", linfo.line_offset);
+ if (linfo.name[0])
+ fprintf(stdout, " %s", linfo.name);
+ else
+ fprintf(stdout, " unnamed");
+ if (linfo.label[0])
+ fprintf(stdout, " \"%s\"", linfo.label);
+ else
+ fprintf(stdout, " unlabeled");
+ if (linfo.flags) {
+ fprintf(stdout, " [");
+ print_flags(linfo.flags);
+ fprintf(stdout, "]");
+ }
+ fprintf(stdout, "\n");
+
}
-free_chrdev_name:
+exit_close_error:
+ if (close(fd) == -1)
+ perror("Failed to close GPIO character device file");
free(chrdev_name);
-
return ret;
-
}
void print_usage(void)